#include "bootpack.h"

void init_gdtidt(void)
{
    struct SEGMENT_DESCRIPTOR *gdt = (struct SEGMENT_DESCRIPTOR *) ADR_GDT;
    struct GATE_DESCRIPTOR *idt = (struct GATE_DESCRIPTOR *) ADR_IDT;
    int i;

    /* GDT 初始化 */
    for (i = 0; i <= LIMIT_GDT / 8; i++) {
        set_segmdesc(gdt + i, 0, 0, 0);
    }
    set_segmdesc(gdt + 1, 0xffffffff, 0x00000000, AR_DATA32_RW);
    set_segmdesc(gdt + 2, LIMIT_BOTPAK, ADR_BOTPAK, AR_CODE32_ER);
    
    load_gdtr(LIMIT_GDT, ADR_GDT);

    /* IDT 初始化 */
    for (i = 0; i <= LIMIT_IDT / 8; i++) {
        set_gatedesc(idt + i, 0, 0, 0);
    }

    load_idtr(LIMIT_IDT, ADR_IDT);

    /* 注册 IDT */
    set_gatedesc(idt + 0x0c, (int) asm_inthandler0c, 2 * 8, AR_INTGATE32);
    set_gatedesc(idt + 0x0d, (int) asm_inthandler0d, 2 * 8, AR_INTGATE32);

    set_gatedesc(idt + 0x20, (int) asm_inthandler20, 2 * 8, AR_INTGATE32);
    set_gatedesc(idt + 0x21, (int) asm_inthandler21, 2 * 8, AR_INTGATE32);

    set_gatedesc(idt + 0x2c, (int) asm_inthandler2c, 2 * 8, AR_INTGATE32);
    set_gatedesc(idt + 0x40, (int) asm_zic_api,      2 * 8, AR_INTGATE32 + RING3_PREMIS);

    return;
}

void set_segmdesc(struct SEGMENT_DESCRIPTOR *sd, unsigned int limit, int base, int ar)
{
    if (limit > 0xfffff) {
        ar |= 0x8000;
        limit /= 0x1000;
    }
    sd->limit_low    = limit & 0xffff;
    sd->base_low     = base & 0xffff;
    sd->base_mid     = (base >> 16) & 0xff;
    sd->access_right = ar & 0xff;
    sd->limit_high   = ((limit >> 16) & 0x0f) | ((ar >> 8) & 0xf0);
    sd->base_high    = (base >> 24) & 0xff;
    return;
}

void set_gatedesc(struct GATE_DESCRIPTOR *gd, int offset, int selector, int ar)
{
    gd->offset_low   = offset & 0xffff;
    gd->selector     = selector;
    gd->dw_count     = (ar >> 8) & 0xff;
    gd->access_right = ar & 0xff;
    gd->offset_high = (offset >> 16) & 0xffff;
    return;
}
